CHICAGO - Three people, including a 3-year-old boy, are in critical condition Friday after an apparent gang-related shooting at a neighborhood basketball court in Chicago that left up to 13 people injured.

At least 10 ambulances were sent to the site in Chicago's Back of the Yards neighborhood after 10 p.m. Thursday, WGN-TV reports. No deaths were reported.

Police spokesman Ron Gaines said that victims were being interviewed to determine the circumstances of the shooting. As of Friday morning, no arrests have been reported.

A witness, Julian Harris, told the Chicago Sun-Times that dreadlocked men fired at him from a gray sedan before turning toward Cornell Square Park and firing at people. He said his 3-year-old nephew was wounded in the cheek.

"They hit the light pole next to me, but I ducked down and ran into the house," Harris said. "They've been coming round here looking for people to shoot every night, just gang-banging stuff. It's what they do."

The Chicago Tribune quotes police as saying the boy suffered a gunshot wound to the head at an ear that exited through his mouth. Chicago Fire Department officials said he was in critical condition. The Tribune quotes family members as identifying the boy as Deonta' -- pronounced Deontay -- who was nicknamed Tay Man.

Officials at Mount Sinai hospital said Friday that the boy was a patient there but could not provide an update on his condition. Two other victims were also in critical condition. The others were reported in serious to fair condition.

Officer Amina Greer Greer told the Associated Press early Friday that police have since identified a 13th victim, a 33-year-old woman with a gunshot wound to the back near one shoulder. Other victims included a 15-year-old and a 17-year-old. The injuries ranged from shots to the heads to wounds in the knee and buttocks.

Police also said the shootings appeared to be gang-related.

"Senseless and brazen acts of violence have no place in Chicago and betray all that we stand for," Mayor Rahm Emanuel said in a statement Friday. "The perpetrators of this crime will be brought to justice and prosecuted to the full extent of the law. I encourage everyone in the community to step forward with any information and everyone in Chicago to continue their individual efforts to build stronger communities where violence has no place."

Three weeks ago an outbreak of violence during the Labor Day weekend left eight people dead and 20 injured.

The Chicago police department responded by paying overtime to add patrols to some neighborhoods, including the Back of the Yards, where Thursday's shooting took place.

Crime statistics released this week by the FBI showed that Chicago, with 500 murders in 2012, replaced New York, with 419, as the murder capital of the U.S.